The 39" PRO is the most popular model, trusted by home users and professional studios alike for its unmatched performance, durability, and versatility. With adjustable 4-knot cords for a firm to extra-firm bounce, it supports everything from high-intensity cardio to sculpting and balance work. Available in a wide range of colors, the 39" PRO lets you find your TRUE COLOR and make your fitness routine feel personal, powerful, and uniquely yours.